Dunsley Tank Heating Problems

[WaggyH]

Hi, I have a log burner and oil fired boiler feeding into a 'dunsley' neutralizer tank. The system (gravity fed) has worked fine for a number of years, except that it can take 20 to 30 minutes for the rads to get hot first thing in the morning and burns a lot of oil in the process.
I am thinking of fitting a 12v immersion heater to the hot water tank, running off a stream continuously via a hydro generator. This will hopefully give permanent hot water in the tank. Would it then be possible to feed hot water from the tank, via a non return valve, perhaps on a timer, back into the dunsley. This could then be used to keep the water in the dunsley at a reasonable temperature for when the heating first came on

 

[SimonG]

Nope, fix the issue, dont try to mask it.

I'd be looking at the thermostats on the Dunsley unit to check correct operation.

 

[snowhead]

It won't be the Dunsley that's soaking up the heat and trying preheat it won't solve the issue.
It's more likely the oil boiler is somehow circulating back through the Log burner or into the hot water cylinder.
Have you checked when the boiler first comes on to see if there is flow anywhere other than the heating circuit?
Are the rads zoned, could you delay 1 zone coming on to see how long the rest take to warm up?

How many rads on the system and how cold it the house just before the heating comes on, is the house in a cold remote location?

Can you post pictures of the pipwork connections to the Dunsley, with labels for the pipes if the pipework is not obvious.

 

[WaggyH]

It won't be the Dunsley that's soaking up the heat and trying preheat it won't solve the issue.
It's more likely the oil boiler is somehow circulating back through the Log burner or into the hot water cylinder.
Have you checked when the boiler first comes on to see if there is flow anywhere other than the heating circuit?
Are the rads zoned, could you delay 1 zone coming on to see how long the rest take to warm up?

How many rads on the system and how cold it the house just before the heating comes on, is the house in a cold remote location?

Can you post pictures of the pipwork connections to the Dunsley, with labels for the pipes if the pipework is not obvious.

Thanks for your reply. Once the oil boiler is on, the hot water does also flow round the wrap around wood burner, but the pipe run is not that long. I did ask the plumber about fitting a non return valve to prevent flow to the wood burner but he seemed to think this would cause other problems. As i say, the system is working fine apart from the heat up time. The property is quite rural and is normally quite cold first thing. There are 8 rads in the cottage. Three of these are the old type column rads which take a lot more water. The dunsley and hwt are in a compact space and heavily insulated. A photo would be tricky.

 

[Best]

Sounds weird that the oil boiler can put heat around the wood burner?
The neutraliser is supposed to prevent that if system designed and piped correctly.